feat(opencode): gzip compress json responses for up to 97% smaller payload

[brittlewis12]

What does this PR do?

fixes #10475

Large sessions can have 20MB+ JSON payloads which can take 20-30s to transfer over mobile networks. Gzip compression reduces this dramatically, improving mobile load times perceptibly. In one case a 400-message session went from 20-30s (23.9MB) to ~5s (580KB).

I attempted to use hono’s own compression middleware but that seemed to break the client, so I opted to implement a middleware with bun’s gzip compression directly.

How did you verify your code works?

ran the server locally (bun run dev web) and tested a session w 400 messages on my phone against v1.1.47:

before (v1.1.47)

custom client logging:

[sync] fetch complete: 19071ms, size=22.73MB
[sync] processing (filter/sort/clone messages): 29ms, count=400
[sync] batch/reconcile complete: 612ms
[sync] TOTAL: 19712ms

23.9MB for that one session:

after (this PR)

custom client logging:

[sync] fetch complete: 5096ms, size=22.73MB
[sync] processing (filter/sort/clone messages): 35ms, count=400
[sync] batch/reconcile complete: 402ms
[sync] TOTAL: 5533ms

23.9MB -> 580KB for that one session

[github-actions]

Hey! Your PR title perf(server): gzip compress session messages response doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

See CONTRIBUTING.md for details.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

No duplicate PRs found

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.

[brittlewis12]

but it does have a linked issue? #10475

[brittlewis12]

took a quick pass over other potentially desirable candidates for response gzip compression — i think the main ones that stood out were /file/contents and /:sessionId/diff

if you folks would like i’m happy to extend this to those as well, but i figured i’d stick with the pain i’ve actually felt!

edit: just implemented for all json responses

[github-actions]

Closing this pull request because it has had no updates for more than 60 days. If you plan to continue working on it, feel free to reopen or open a new PR.